Brodak Retarder , how silly can you get with it?

Stuka Stunt Main Forum · 18 of 18 known posts recovered

TigreST · Aug 08, 2001 12:51 PM

Gents and Ladies(if your out there?),
Brodak states on the bottles/cans of retarder and in other literature not to use any more then 20% (working from memory here) of this material (retarder) in any of your mixes. I'm curious as to what the end result would be for having done this, pushed the percentage that is? What happens if you push the use to 30, 40 or 50% of the total thinners make up? What are your current blending mixing practices with Brodak materials?

My current practice of 50/50 dope/thinners, with 75/25 thinner to retarder , seems to be working very well given the heat and humidity we are dealing with here in Sarnia, Ontario at the moment. The body (human body) is giving up before the paint finish is it seems. Having sprayed both color and candy coats I've now decided to ask what the rest of the world was doing, ha ha, ..cart before the horse again. I welcome any feedback fella's.

Tony

Jake · Aug 08, 2001 01:32 PM

#1 source

Oh, fiddle. I have pushed the retarder/dope mix to at least 50/50 in my current very sorry climate, probably more than that at times. It is a fluid situation; what is ok today may be a mess tomorrow!

Steve Fitton · Aug 08, 2001 02:04 PM

#2 source

I met a fellow at Brodaks 2000 who had a gorgeous Brodak nobler with all Brodak dope finish with 30% retarder used. The result? three months after he had finished the ship the dope was soft enough that if you were not very careful handling the plane you would still leave fingerprints in the surface-not dirt marks but actual impressions in the surface. High levels of retarder might work sometimes but burn you at a later time. I've had to use 10% retarder just to slow drying time a bit but somewhere in the 25-35% range you can get in trouble.

Steve

Jake · Aug 08, 2001 02:10 PM

#3 source

LAST EDITED ON Aug-08-01 AT 02:15 PM (EST)

And again, it all depends on where you are, when you are. I have had stuff dry so fast at 30% retarder/dope mix that it was like pebble-grain when it hit the surface. The only hard and fast rule is, that NOTHING is ALWAYS so....

JAK

captcurt · Aug 09, 2001 06:48 AM

#9 source

A garage-sale de-humidifier is a much better solution for painting during the summer!

Soft finish is a pretty general result with over-retarded thinners.

FWIW

Curt

peabody · Aug 08, 2001 04:41 PM

#4 source

Interestingly, Windy is a big proponent of retarder, while John (Brodak) isn't? The weather is essentially the same, although John paints indoors in a room with a pretty good fan, while Winfred scampers up the stairs and squirts stuff on over his patio.

I believe that both are extremely durable finishes, and neither exhibit "blush".

John paints up 5-6 models per year, Windy one.

I do know that the retarder seems to penetrate a bunch, exposing the painter to discoloring a finish coat because the retarder has penetrated through to the base.

See Ya

Peabody

Curt Contrata · Aug 08, 2001 05:58 PM

How silly can you get with it? Not Very!#5 source

Use extreme caution when using Retarder and only use it when you really have to. The only time blushing becomes a problem is on the very last coat of clear so, when possible, avoid using Retarder by waiting another day to spray. I live in Florida and there are few places more humid than here yet we can get away without using it. If you insist on using Retarder, use as little as needed to solve the problem to avoid creating a bigger one.

Curt

Jake · Aug 08, 2001 06:44 PM

RE: How silly can you get with it? A lot....#6 source

It don't work thata way.
It is ALL relative to a BUNCH of inter-related factors.
What works for me, won't necessarily work for you, just because our climate might be similar, doesn't mean I can finish my model in exactly the same way you do you yours, and acheive identical results. Way too many things can vary!
I have used 50/50 retarder/dope mix, and the stuff is dry to touch in less than 15 minutes, and NO problems. I have also tried to spray a mix as you described and had it look like sandpaper under the same conditions. DON'T make a blanket statement "This is always so!".

JAK

Howard Rush · Aug 08, 2001 10:25 PM

RE: How silly can you get with it? A lot....#7 source

You using Brodak, JAK?

LNeumann · Aug 08, 2001 11:16 PM

RE: How silly can you get with it? A lot....#8 source

I think what Howard is alluding to, John, is that Brodak dope (and thinner) is a very quick drying dope. and that is one of th beauties of it. When you add retarder in large amounts you will totally destroy these characteristics. The usual result is meltdown (bleeding down into the underlayers), and a total mess. I think that is why John Brodak recommends no more than 20% retarder for even extreme situations.

I really don't like using retarder at all. If it is extremely hot, well, maybe. A little. If it is extremely humid and you need to slow it down so it doesn't blush, well, there is where the problems come in. If you slow it down that much, well, you are risking adding all sorts of other problems with it.

Maybe there are some dopes and some extremely fast drying thinners where you can mix 50-50, but I sure wouldn't advise doing it with Brodak.

Leonard Neumann

Brett Buck · Aug 09, 2001 10:09 AM

RE: How silly can you get with it? A lot....#10 source

>It don't work thata way.

I tend to weight concours winner's opinions pretty highly.

Brett

Jake · Aug 09, 2001 05:00 PM

RE: How silly can you get with it? A lot....#11 source

I tend to try it myself first and see if it works, under my conditions. Considering the number of times through the years I have experienced in the firearms field the amount of information from experts that has been either folklore, or partly true, sometimes completely false, sometimes actually true, as I found out on trying a given thing myself, I don't take anyone's word for anything anymore. The Brodak "rejuvenator" is wonderful; fixes a very sad looking finish that I would have stripped and redone otherwise.
I generally favor Aerogloss myself, as I am not a great fan of butyrate dope, and most all my stuff is diesels anyway, although I do use Randolph and some Brodak from time to time.

JAK

mcm · Aug 10, 2001 01:32 AM

RE: How silly can you get with it? A lot....#12 source

Am I missing something here? Isn't all Butyrate dope basically very similar to lacquer? I think everyone agrees that the heat/humidity index has everything to do with how much (if any) retarder you use. Is there something magically different with Brodak dope (didn't John purchase the Randolph or some other line to remarket) than any other Butyrate? I have used Brodak's purple and clear and had no problems. Mostly, I have used SIG or Stits. I know that with whatever dope or lacquer I have used, sometimes I got it right and other times I have sanded like heck. Of course, with clear lacquers (and most dopes I've used), they will "melt" into the prior coats. One friend does not even bother to dust after he sands his clears, and he gets great finishes. I've honestly never measured how much thinner or retarder I use. It's always been a "gut feeling" that has usually been close, but sometimes been very, very wrong. I do think that there are some days that, no matter what you do, it is not good to spray this stuff absent a climate-controlled environment.

Jake · Aug 10, 2001 10:41 AM

RE: How silly can you get with it? A lot....#13 source

LAST EDITED ON Aug-10-01 AT 10:51 AM (EST)

There are lacquers and there are lacquers. Aerogloss is an acrylic lacquer. Butyrate dope IS related to lacquers and to nitrate, but that is like saying most cars have four wheels. Really all different animals.
Butyrate originated because of (full-size) aircraft concerns of fire resistance just before WW-2. It doesn't burn as easily as nitrate does, and it is also more fuel-resistant to alcohol based fuels than nitrates are, BUT it also doesn't stick to the structure (especially to metal or sharp corners or edges) as well as nitrate (or acrylic lacquer) will.
Automobile lacquer is an acrylic lacquer; it is much more fuel-resistant than any butyrate dope, it's main drawback is it cracks if not well plasticized.
As to Brodak, yes it is made by Randolph for Brodak, using a somewhat different formula better suited to models (or so it is said). Personally, I just buy regular old Randolph clear in gallons from the local aircraft supply house (as one of the greats of PA advised me to do years ago), thin, tint or pigment, hit it with retarder as needed, and let it go at that ...

JAK

TigreST · Aug 10, 2001 03:50 PM

RE: How silly can you get with it? A lot....#14 source

LAST EDITED ON Aug-10-01 AT 03:53 PM (EST)

Guys,
I've just read in the latest Stunt News, under "Crash Repairs" by "Mr Gloss" Windy that he does sample shots to test the waters for blush, then adds retarder up to only 10%, and this is only for the clear coats, ..if memory serves.

This I take to mean retarder is added to equal 10% of the total volume of the dope/thinner mix i.e.: 10 oz's volume of total mixture, to this add one ounce of retarder if required.

If this thinking is correct I've only been using approx. 12.5% retarder in my total mixture volume. And as stated to date, I'm seeing no ill effects.

Regarding temp. and humidity numbers: I shot Brodak at the above previously mentioned percentages, in temperature of 33C/91F range and upwards of 60-70% humidity,(saw this number on The Weather Channel yesterday. ..was it a cooker of a day!!!, ..nicer today) I guess based on comments here, we tend to do and use what works best for each of us, as is always the case. I just started at the max recommended amount given the outrageous weather we were having here, and because I've gotta get this sucker in the air this year, at long last.

An earlier color shoot of Brodak white did produce some blush, ..this is when I doubled the shot or retarder in my thinner/retarder mix to the 75/25 ratio. If the weather holds as is (beauty of a day here today)I'll be back at it tomorrow morning, this time I won't be pushing the retarder as hard,...unless I need to! Thanks fella's.

Tone

Jake · Aug 10, 2001 03:55 PM

RE: How silly can you get with it? A lot....#15 source

Yes, it all depends. I have had a mix that works great one day, be not what was needed a day or two later, sometimes on the same day!
You have to adjust for where you are, when you are.

TigreST · Aug 10, 2001 04:06 PM

RE: How silly can you get with it? A lot....#16 source

Gents,
One other question: What do you mix to (dope/thinner) when perfect spraying conditions exist? What's your base line best mix spraying with Brodak products, forgetting the need for retarder, as in perfect conditions we assume it's not needed. Leonard you stated that you do not go near 50/50, ..what's your base mix ratio?

Tone

TigreST · Aug 14, 2001 12:30 AM

RE: How silly can you get with it? A lot....#17 source

Well to answer my own question it would seem that a near perfect mix would still be 50/50 dope to thinners, ..with out the retarder. ( I think that's the recommend mix from Brodak, and is used by "Mr Gloss" a.k.a Windy) I sprayed the last of my candy color 1/4 inch wide stripe tonight before dinner in what I think is near perfect conditions, 70 deg's low humidity at 20-25% (low for around here lately that is). I was using the same candy orange/red mix I had poured for the earlier shoots, and it had retarder in it, ..don't think I needed it this time out. This was a 12.5% mix of retarder (based on total volume of the 50/50 mix of dope/thinner) It did take longer to dry, a good deal longer, but other then that I've seen no ill effects from it's use. I can only hope that I have a day like today to shoot the clear coats which are coming up. As per other comments, ..may be a good idea to wait for the "perfect day" for this clear shoot.

Tone "Over and Out"